Merge tag 'locks-v3.18-1' of git://git.samba.org/jlayton/linux

[pandora-kernel.git] / drivers / tty / tty_io.c

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index aea3b66..16a2c02 100644 (file)
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -908,8 +908,7 @@ void no_tty(void)
  *     stop_tty        -       propagate flow control
  *     @tty: tty to stop
  *
- *     Perform flow control to the driver. For PTY/TTY pairs we
- *     must also propagate the TIOCKPKT status. May be called
+ *     Perform flow control to the driver. May be called
  *     on an already stopped device and will not re-call the driver
  *     method.
  *
@@ -919,64 +918,58 @@ void no_tty(void)
  *     but not always.
  *
  *     Locking:
- *             Uses the tty control lock internally
+ *             flow_lock
  */
 
-void stop_tty(struct tty_struct *tty)
+void __stop_tty(struct tty_struct *tty)
 {
-       unsigned long flags;
-       spin_lock_irqsave(&tty->ctrl_lock, flags);
-       if (tty->stopped) {
-               spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+       if (tty->stopped)
                return;
-       }
        tty->stopped = 1;
-       if (tty->link && tty->link->packet) {
-               tty->ctrl_status &= ~TIOCPKT_START;
-               tty->ctrl_status |= TIOCPKT_STOP;
-               wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
-       }
-       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
        if (tty->ops->stop)
                (tty->ops->stop)(tty);
 }
 
+void stop_tty(struct tty_struct *tty)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&tty->flow_lock, flags);
+       __stop_tty(tty);
+       spin_unlock_irqrestore(&tty->flow_lock, flags);
+}
 EXPORT_SYMBOL(stop_tty);
 
 /**
  *     start_tty       -       propagate flow control
  *     @tty: tty to start
  *
- *     Start a tty that has been stopped if at all possible. Perform
- *     any necessary wakeups and propagate the TIOCPKT status. If this
- *     is the tty was previous stopped and is being started then the
- *     driver start method is invoked and the line discipline woken.
+ *     Start a tty that has been stopped if at all possible. If this
+ *     tty was previous stopped and is now being started, the driver
+ *     start method is invoked and the line discipline woken.
  *
  *     Locking:
- *             ctrl_lock
+ *             flow_lock
  */
 
-void start_tty(struct tty_struct *tty)
+void __start_tty(struct tty_struct *tty)
 {
-       unsigned long flags;
-       spin_lock_irqsave(&tty->ctrl_lock, flags);
-       if (!tty->stopped || tty->flow_stopped) {
-               spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+       if (!tty->stopped || tty->flow_stopped)
                return;
-       }
        tty->stopped = 0;
-       if (tty->link && tty->link->packet) {
-               tty->ctrl_status &= ~TIOCPKT_STOP;
-               tty->ctrl_status |= TIOCPKT_START;
-               wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
-       }
-       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
        if (tty->ops->start)
                (tty->ops->start)(tty);
-       /* If we have a running line discipline it may need kicking */
        tty_wakeup(tty);
 }
 
+void start_tty(struct tty_struct *tty)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&tty->flow_lock, flags);
+       __start_tty(tty);
+       spin_unlock_irqrestore(&tty->flow_lock, flags);
+}
 EXPORT_SYMBOL(start_tty);
 
 /* We limit tty time update visibility to every 8 seconds or so. */
@@ -1030,14 +1023,14 @@ static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
        return i;
 }
 
-void tty_write_unlock(struct tty_struct *tty)
+static void tty_write_unlock(struct tty_struct *tty)
        __releases(&tty->atomic_write_lock)
 {
        mutex_unlock(&tty->atomic_write_lock);
        wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
 }
 
-int tty_write_lock(struct tty_struct *tty, int ndelay)
+static int tty_write_lock(struct tty_struct *tty, int ndelay)
        __acquires(&tty->atomic_write_lock)
 {
        if (!mutex_trylock(&tty->atomic_write_lock)) {
@@ -1224,6 +1217,35 @@ ssize_t redirected_tty_write(struct file *file, const char __user *buf,
        return tty_write(file, buf, count, ppos);
 }
 
+/**
+ *     tty_send_xchar  -       send priority character
+ *
+ *     Send a high priority character to the tty even if stopped
+ *
+ *     Locking: none for xchar method, write ordering for write method.
+ */
+
+int tty_send_xchar(struct tty_struct *tty, char ch)
+{
+       int     was_stopped = tty->stopped;
+
+       if (tty->ops->send_xchar) {
+               tty->ops->send_xchar(tty, ch);
+               return 0;
+       }
+
+       if (tty_write_lock(tty, 0) < 0)
+               return -ERESTARTSYS;
+
+       if (was_stopped)
+               start_tty(tty);
+       tty->ops->write(tty, &ch, 1);
+       if (was_stopped)
+               stop_tty(tty);
+       tty_write_unlock(tty);
+       return 0;
+}
+
 static char ptychar[] = "pqrstuvwxyzabcde";
 
 /**
@@ -1544,13 +1566,14 @@ static void release_one_tty(struct work_struct *work)
        struct tty_struct *tty =
                container_of(work, struct tty_struct, hangup_work);
        struct tty_driver *driver = tty->driver;
+       struct module *owner = driver->owner;
 
        if (tty->ops->cleanup)
                tty->ops->cleanup(tty);
 
        tty->magic = 0;
        tty_driver_kref_put(driver);
-       module_put(driver->owner);
+       module_put(owner);
 
        spin_lock(&tty_files_lock);
        list_del_init(&tty->tty_files);
@@ -3019,6 +3042,7 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
        INIT_WORK(&tty->hangup_work, do_tty_hangup);
        mutex_init(&tty->atomic_write_lock);
        spin_lock_init(&tty->ctrl_lock);
+       spin_lock_init(&tty->flow_lock);
        INIT_LIST_HEAD(&tty->tty_files);
        INIT_WORK(&tty->SAK_work, do_SAK_work);